| Discovery[1] | |
|---|---|
| Discovered by | C. Shoemaker |
| Discovery site | Palomar Obs. |
| Discovery date | 16 February 1985 |
| Designations | |
| (5426) Sharp | |
Named after | Robert P. Sharp (Americangeomorphologist)[2] |
| 1985 DD | |
| main-belt · (inner)[1] Hungaria[3][4] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 31.94 yr (11,667 days) |
| Aphelion | 2.1828AU |
| Perihelion | 1.7273 AU |
| 1.9550 AU | |
| Eccentricity | 0.1165 |
| 2.73yr (998 days) | |
| 319.59° | |
| 0° 21m 38.16s / day | |
| Inclination | 23.795° |
| 88.178° | |
| 67.532° | |
| Knownsatellites | 1[5][6](suspected;P: 24.22 h) |
| Physical characteristics | |
| Dimensions | 2.033±0.343 km[7][8] 3.85 km(calculated)[4] |
| 4.56±0.01 h[9] 4.5609±0.0001h[5][a] | |
| 0.30(assumed)[4] 1.000±0.000[7][8] | |
| E[4] | |
| 13.7[7] · 14.0[1][4] · 15.16±0.21[10] | |
5426 Sharp, provisional designation1985 DD, is a brightHungaria asteroid and suspectedbinary system from the inner regions of theasteroid belt, approximately 2–3 kilometers in diameter. It was discovered on 16 February 1985, by American astronomerCarolyn Shoemaker atPalomar Observatory, California, and named after American geologistRobert P. Sharp.[2][3]
Sharp is a brightE-type asteroid and a member of theHungaria family, which form the innermost dense concentration of asteroids in theSolar System. It orbits the Sun in theinner main-belt at a distance of 1.7–2.2 AU once every 2 years and 9 months (998 days). Its orbit has aneccentricity of 0.12 and aninclination of 24° with respect to theecliptic.[1] The body'sobservation arc begins with its official discovery observation at Palomar, as noprecoveries were taken, and no prior identifications were made.[3]
According to the surveys carried out by NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Sharp measures 2.033 kilometers in diameter, and its surface has an outstandingly highalbedo of 1.000.[7][8] The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.30 – a compromise value between 0.4 and 0.2, corresponding to the Hungaria asteroids both as family and orbital group – and calculates a diameter of 3.85 kilometers with anabsolute magnitude of 14.0.[4]
The high albedo derived from the WISE-observations indicate thatSharp belongs to thecollisional Hungaria asteroids (rather than just its orbital group), which is thought to have originated from the same parent body that shattered into fragments in an ancient asteroid collision. The high albedo is due to the magnesium-rich mineralenstatite, which led to theE-type in theasteroid spectral type taxonomy.[5]
A first rotationallightcurve ofSharp was obtained in November 2011, from photometric observations by American astronomerBrian Warner at his Palmer Divide Observatory (716) in Colorado (U=2).[9] Lightcurve analysis indicated the possibility thatSharp could be orbited by aminor-planet moon nearly every 24 hours.
In 2014/15,Sharp was re-examined by Brian Warner in a collaboration with astronomers Vladimir Benishek atBelgrade Astronomical Observatory, Serbia, and Andrea Ferrero at Bigmuskie Observatory in Italy (B88). The European collaboration was required because the satellite's orbital period was expected to be almost exactly an Earth day, and therefore synchronous with Earth, which would have made it impossible to obtain photometric data points covering the entire lightcurve from just one single location.[5]
The obtained lightcurves[a] from the combined photometric observations gave a well-definedrotation period of 4.5609 hours, a brightness variation of 0.18magnitude (U=3), and orbital period of 24.22 hours for the asteroid's moon. However, as no mutual occultation/eclipsing events were observed, thebinary nature ofSharp remains unconfirmed.[5] The "Johnstonsarchive" estimates that the moon has asemi-major axis of 4.5 kilometers.[6] No diameter estimate for the moon was published, as a secondary-to-primary mean-diameter ratio could not be derived.
Thisminor planet was named in honor of American geomorphologistRobert P. Sharp (1911–2004), American professor of geology at Caltech, expert on glaciers, the movement of sand dunes and the geology of Mars. The Martian craterRobert Sharp and mountainMount Sharp (now officiallyAeolis Mons), were named in his honor. Mount Sharp rises from the middle of Gale Crater, which is explored by the MarsCuriosity rover since 2012.[2] The approved naming citation was published by theMinor Planet Center on 17 March 1995 (M.P.C. 24917).[11]
